Intentionally Polluting Lakes

Deliberately adding excessive phosphorus to a freshwater lake results in extensive algae growth on the water surface

Polluting lakes on purpose in the name of science. This is everyday life at the Experimental Lakes Area (ELA), a collection of 58 freshwater lakes in the province of Ontario, Canada. Under government protection since 1968, these lakes are designated for the sole purpose of conducting experiments over an entire lake ecosystem. These lakes are self-contained, so scientists are able to pollute individual lakes without disturbing others. They monitor any effects that occur to the water, soil, plants and aquatic life. Once the experiments have been completed, the lakes are returned to their original condition. Experiments can last years, even decades, making the ELA the only location of its kind in the world.

Some examples of research that has been done at the ELA:

Algal blooms, a big problem in freshwater lakes, are caused by excess plant nutrients from fertilizer runoff and untreated sewage entering waterways. Carbon, nitrogen, and phosphorus were thought to play key roles in the algal growth, but how much was unknown. Research done at the ELA found that excess phosphorus was the primary nutrient responsible for the algae growth. Increased carbon or nitrogen had little effect.

Acid rain was believed to be killing fish by making lakes more acidic. Air pollution from power plants and factories was seen as responsible. These companies argued against this, saying fish can live in more acidic water and that something else was killing them. The companies tested this by adding acid water to fish tanks and found that the fish did survive. The ELA ran a similar study, except they added acid water to an entire lake. While this did not directly affect the fish, it did kill the smaller creatures, the main food source for the fish. The fish ended up starving.

High estrogen levels in water can cause male fish to turn into females. This is an issue in regions where use of the human birth control pill is common. The seriousness of this issue was unknown until the ELA added estrogen to a lake and found it nearly drove fish in the lake extinct.

Each of the above studies had enough influence to lead to tighter regulations regarding pollution and water management. What made their results so valuable was that these tests were done using entire lakes, something not possible anywhere else in the world.

Current projects at the Experimental Lakes Area look at how a changing climate could potentially alter fish populations, how using fish farms in freshwater lakes as a food source affects their surrounding environment, and finding how mercury pollution enters lakes so that methods can be devised to prevent it. However, the Canadian government, the primary source of funding for the ELA, has said it will shut down the facility in 2013. This places all current projects in jeopardy, as well as any future research that can be done there.